✓ Preheat the oven to 375°F (190°C).

✓ In a large skillet, cook the ground beef over medium heat until browned, about 8 minutes. Drain excess fat and return the beef to the skillet.

✓ Add the diced onion and minced garlic, and cook for another 2 minutes until the onion softens.

✓ Stir in the Worcestershire sauce and mustard (if using), and let the mixture simmer for 2 minutes to blend the flavors.

✓ In a medium bowl, whisk together the flour, baking powder, salt, and black pepper.

✓ Add the milk and eggs, and whisk until smooth.

✓ Pour this mixture into the skillet with the beef and vegetables, stirring to combine.

✓ Cook over low heat for 3 to 5 minutes, until the mixture thickens slightly.

✓ Transfer the filling into a prepared pie crust, spreading it evenly.

✓ Sprinkle the shredded cheddar cheese on top of the filling.

✓ Bake the pie for 35 to 40 minutes, or until the top is golden brown and the filling is set.

✓ Allow the pie to cool for at least 10 minutes before slicing.